Vitreous fluid of db/db mice exhibits alterations in angiogenic and metabolic factors consistent with early diabetic retinopathy.

BACKGROUND

This study evaluated the postulate that the vitreous of diabetic db/db mice, a genetic model of type 2 diabetes that manifests hyperglycemia and insulin resistance, exhibits alterations in angiogenic and metabolic factors that reflect abnormalities in the retinal microvasculature participatory in the pathogenesis of diabetic retinopathy.

METHODS

Vitreous obtained from db/db and age-matched nondiabetic db/m mice was analyzed by Western blot for pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF), by immunoassay for type IV collagen, and by measurement of TBARs for lipid peroxide products.

RESULTS

Compared to nondiabetic db/m controls, vitreous from db/db mice contained decreased PEDF and increased VEGF (VEGF:PEDF relative ratio 2.2 +/- 0.3 and 1.0 +/- 0.1 in db/db vs. db/m, respectively; p < 0.05), and elevated concentrations of lipid peroxide products (187 +/- 43 and 84 +/- 15 ng/ml in db/db vs. db/m, respectively; p < 0.05) and type IV collagen (5.2 +/- 0.7 and 3.1 +/- 0.4 nmol/ml in db/db vs. db/m, respectively; p < 0.05). These changes were observed at age 18-20 weeks, consistent with an early stage in the development of retinal microvascular pathology.

CONCLUSIONS

The findings support the potential usefulness of vitreous from the db/db mouse as a model tissue for investigation of pathogenetic factors and assessment of therapeutic interventions in early diabetic retinopathy.